Based on the floating reference theory, a new method for extracting the net analyte signal （NAS） is proposed. The noise background subspace is spanned by spectra at the floating radial reference point, and then, the spectra at the measurement point are projected on the subspace. Thereafter, the glucose concentrations in intralipid solutions are investigated through Monte Carlo simulation and experiments, and the partial least squares （PLS） models with and without NAS analysis are built. The root mean square errors of calibration and prediction reach to 28.87% and 27.33%, respectively. The results confirm the existence of information induced by glucose concentration variations as well as the validity of the floating reference theory.
Tissue optical clearing by use of optical clearing agents(OCAs)has been proven to have potential to reduce the highly scattering effect of biological tissues in optical techniques.However,the difference in tissue samples could lead to unreliable results,making it difficult to quantitatively control the dose of OCAs during the course of tissue optical clearing.In this work,in order to study the effects of optical clearing,we customized tissue-like phantoms with optical properties of some biological tissue.Diffuse reflectance and total transmittance of tissue-like phantoms with different OCAs(DMSO or glycerol)and porcine skin tissues were measured.Then optical property parameters were calculated by inverse adding-doubling(IAD)algorithm.Results showed that OCAs could lead to a reduction in scattering of tissue-like phantoms as it did to porcine skin tissue in vitro.Furthermore,a series of relational expressions could be fit to quantitatively describe the relationship between the doses of OCAs and the reduction of scattering effects.Therefore,proper tissue-like phantom could facilitate optical clearing to be used in quantitative control of tissue optical properties,and further promote the application potential of optical clearing to light-based noninvasive diagnostic and therapeutic techniques.
